Estradiol distribution and penetration in rat skin after topical application, studied by high resolution autoradiography.
Transdermal pathways and targets in the skin for estradiol were investigated using dry-mount autoradiography. 3H-estradiol-17 beta was applied at doses of 30.1 pmol, 120.4 pmol and 301 pmol/cm2 to shaved rat skin in the dorsal neck region. Vehicles were DMSO, ethylene glycol or sesame oil. After 2 h of topical treatment with 30.1 pmol 3H-estradiol x cm-2 dissolved in DMSO a distinct cellular distribution was apparent. Target cells with concentrations of radioactivity were found in epidermis, sebaceous glands, dermal papillae of hair and fibroblasts. After treatment with 120.4 and 301 pmol/cm2, a penetration gradient of radioactivity was recognizable however it masked specific cellular and subcellular uptake. The stratum corneum accumulated and retained radioactivity, apparently forming a depot for the hormone. Strong concentration and retention of the hormone was conspicuous in sebaceous glands for more than 24 h, suggesting that sebaceous glands serve as a second storage site for the hormone. In all autoradiograms two penetration pathways to the dermis were visible: one through the stratum corneum and epidermis, the other through the hair canals and hair sheaths.
Bidmon
H J
HJ
Department of Cell Biology and Anatomy, and Pharmacology, University of North Carolina, Chapel Hill 27599.
Pitts
J D
JD
Solomon
H F
HF
Bondi
J V
JV
Stumpf
W E
WE
D000287:Administration, Topical; D000818:Animals; D001345:Autoradiography; D004817:Epidermis / Q000378:metabolism; D004958:Estradiol / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019855:Ethylene Glycol; D005026:Ethylene Glycols; D005260:Female; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012627:Sebaceous Glands / Q000378:metabolism; D012715:Sesame Oil; D012867:Skin / Q000378:metabolism*; D014018:Tissue Distribution
D005026:Ethylene Glycols; D004958:Estradiol; D012715:Sesame Oil; D019855:Ethylene Glycol